Sheet feeding apparatus and image forming apparatus

Abstract

A sheet feeding apparatus includes a stacking surface on which a sheet is stacked, a feed portion configured to feed the sheet in a sheet feeding direction, and first and second detecting portions disposed at positions different from each other in a width direction orthogonal to the sheet feeding direction and so as to overlap with the stacking surface in a view from a height direction orthogonal to the stacking surface. The first and second detecting portions detect height positions which are positions in the height direction of an uppermost sheet. In addition, a control portion stops feeding the sheet by the feed portion based on at least one a height position detected by the first detecting portion and a height position detected by the second portion in feeding the sheet.

What is claimed is: 
     
       1. A sheet feeding apparatus, comprising:
 a stacking surface on which a sheet is stacked; 
 a feed portion configured to feed the sheet stacked on the stacking surface in a sheet feeding direction; 
 first and second detecting portions disposed at positions different from each other in a width direction orthogonal to the sheet feeding direction and so as to overlap with the stacking surface in a view from a height direction orthogonal to the stacking surface, the first and second detecting portions being configured to detect height positions which are positions in the height direction of an uppermost sheet stacked on the stacking surface at the respective positions in the width direction; and 
 a control portion configured to start feeding the sheet stacked on the stacking surface by the feed portion and to stop feeding the sheet by the feed portion, 
 wherein the control portion is configured to stop feeding the sheet based on at least one of a height position detected by the first detecting portion and a height position detected by the second detecting portion in feeding the sheet. 
 
     
     
       2. The sheet feeding apparatus according to  claim 1 , wherein the control portion stops feeding the sheet by the feed portion in a case where a difference between a height position detected by one of the first and second detecting portions before feeding the sheet by the feed portion and a height position detected by the one of the first and second detecting portions in feeding the sheet is larger than a predetermined first value. 
     
     
       3. The sheet feeding apparatus according to  claim 2 , wherein the control portion stops feeding the sheet by the feed portion in a case where a difference between the height position detected by the first detecting portion before feeding the sheet by the feed portion and the height position detected by the first detecting portion in feeding the sheet by the feed portion, and a difference between the height position detected by the second detecting portion before feeding the sheet by the feed portion and the height position detected by the second detecting portion in feeding the sheet by the feed portion are both larger than a predetermined second value and smaller than the predetermined first value. 
     
     
       4. The sheet feeding apparatus according to  claim 1 , wherein the higher height positions of the uppermost sheet are, the larger detection values output by the first and second detecting portions are, and
 the control portion sets a first threshold value for the first detecting portion based on a detection result of the first detecting portion and a second threshold value for the second detecting portion based on a detection result of the second detecting portion before feeding the sheet by the feed portion, and stops feeding the sheet by the feed portion in a case where the first detecting portion detects a detection value larger than the first threshold value or the second detecting portion detects a detection value larger than the second threshold value in feeding the sheet. 
 
     
     
       5. The sheet feeding apparatus according to  claim 4 , wherein the control portion sets a third threshold value smaller than the first threshold value for the first detecting portion based on a detection result of the first detecting portion and sets a fourth threshold value smaller than the second threshold value for the second detecting portion based on a detection result of the second detecting portion before feeding the sheet by the feed portion, and stops feeding the sheet by the feed portion in a case where the first detecting portion detects a detection value larger than the third threshold value and the second detecting portion detects a detection value larger than the fourth threshold value. 
     
     
       6. The sheet feeding apparatus according to  claim 1 , wherein the higher height positions of the uppermost sheet are, the smaller detection values output by the first and second detecting portions are, and
 the control portion sets a first threshold value for the first detecting portion based on a detection result of the first detecting portion and a second threshold value for the second detecting portion based on a detection result of the second detecting portion before feeding the sheet by the feed portion, and stops feeding the sheet by the feed portion in a case where the first detecting portion detects a detection value smaller than the first threshold value or the second detecting portion detects a detection value smaller than the second threshold value in feeding the sheet. 
 
     
     
       7. The sheet feeding apparatus according to  claim 6 , wherein the control portion sets a third threshold value smaller than the first threshold value for the first detecting portion based on a detection result of the first detecting portion and sets a fourth threshold value smaller than the second threshold value for the second detecting portion based on a detection result of the second detecting portion before feeding the sheet by the feed portion, and stops feeding the sheet by the feed portion in a case where the first detecting portion detects a detection value smaller than the third threshold value and the second detecting portion detects a detection value smaller than the fourth threshold value. 
     
     
       8. The sheet feeding apparatus according to  claim 1 , wherein the control portion stops feeding the sheet by the feed portion in a case where a difference between the height position detected by the first detecting portion before feeding the sheet by the feed portion and the height position detected by the first detecting portion in feeding the sheet by the feed portion, and a difference between the height position detected by the second detecting portion before feeding the sheet by the feed portion and the height position detected by the second detecting portion in feeding the sheet by the feed portion are both larger than a predetermined second value. 
     
     
       9. The sheet feeding apparatus according to  claim 1 , wherein the higher height positions of the uppermost sheet are, the larger detection values output by the first and second detecting portions are, and
 the control portion sets a third threshold value for the first detecting portion based on a detection result of the first detecting portion and sets a fourth threshold value for the second detecting portion based on a detection result of the second detecting portion before feeding the sheet by the feed portion, and stops feeding the sheet by the feed portion in a case where the first detecting portion detects a detection value larger than the third threshold value and the second detecting portion detects a detection value larger than the fourth threshold value in feeding the sheet. 
 
     
     
       10. The sheet feeding apparatus according to  claim 1 , wherein the higher height positions of the uppermost sheet are, the smaller detection values output by the first and second detecting portions are, and
 the control portion sets a third threshold value for the first detecting portion based on a detection result of the first detecting portion and sets a fourth threshold value for the second detecting portion based on a detection result of the second detecting portion before feeding the sheet by the feed portion, and stops feeding the sheet by the feed portion in a case where the first detecting portion detects a detection value smaller than the third threshold value and the second detecting portion detects a detection value smaller than the fourth threshold value in feeding the sheet. 
 
     
     
       11. The sheet feeding apparatus according to  claim 1 , wherein the first detecting portion is disposed on a first side with respect to the feed portion in the width direction, and
 the second detecting portion is disposed on a second side, opposite to the first side, with respect to the feed portion in the width direction. 
 
     
     
       12. The sheet feeding apparatus according to  claim 1 , wherein the first and second detecting portions detect height positions of an upstream part in the sheet feeding direction of the uppermost sheet stacked on the stacking surface. 
     
     
       13. The sheet feeding apparatus according to  claim 1 , wherein each of the first and second detecting portion comprises a light emitting portion configured to irradiate the uppermost sheet stacked on the stacking surface with light and a photo-sensing portion configured to receive the light irradiated from the light emitting portion and reflected by the uppermost sheet, and transmits a signal based on a degree of a quantity of light received by the photo-sensing portion to the control portion. 
     
     
       14. The sheet feeding apparatus according to  claim 13 , wherein the light emitting portion irradiates the light in the height direction. 
     
     
       15. The sheet feeding apparatus according to  claim 1 , wherein each of the first and second detecting portions comprises a light emitting portion configured to irradiate the uppermost sheet stacked on the stacking surface with light and a photo-sensing portion configured to receive the light irradiated from the light emitting portion and reflected by the uppermost sheet, and transmits a signal based on a time from when the light emitting portion irradiates the light and until when the light irradiated from the light emitting portion is received by the photo-sensing portion to the control portion. 
     
     
       16. The sheet feeding apparatus according to  claim 15 , wherein the light emitting portion irradiates the light in the height direction. 
     
     
       17. The sheet feeding apparatus according to  claim 1 , wherein each of the first and second detecting portions comprises a turning portion configured to turn so as to keep a contacting condition between the uppermost sheet and the turning portion and a turn detecting portion configured to detect an angle of turn of the turning portion, and transmits a signal based on a degree of the angle of turn to the control portion. 
     
     
       18. The sheet feeding apparatus according to  claim 1 , further comprising a separation portion configured to separate the sheet fed by the feed portion one by one,
 wherein the stacking surface is configured to stack a sheet bundle including a first sheet being the uppermost sheet of the sheet bundle and a second sheet bound with the first sheet, and 
 the first and second detecting portions detect the height positions of a deflection formed on the first sheet by applying a feed force to the first sheet by the feed portion. 
 
     
     
       19. A sheet feeding apparatus, comprising:
 a stacking surface on which a sheet is stacked; 
 a feed portion configured to feed the sheet stacked on the stacking surface in a sheet feeding direction; 
 a first detecting portion comprising a first light emitting portion configured to irradiate an uppermost sheet stacked on the stacking surface with light and a first photo-sensing portion configured to receive the light irradiated from the first light emitting portion and reflected by the uppermost sheet, disposed so as to overlap with the stacking surface in a view of a height direction orthogonal to the stacking surface, and configured to detect a height position which is a position of the uppermost sheet in the height direction based on a time from when the first light emitting portion irradiates the light and until when the light irradiated from the first light emitting portion is received by the first photo-sensing portion; 
 a second detecting portion comprising a second light emitting portion configured to irradiate the uppermost sheet stacked on the stacking surface with light and a second photo-sensing portion configured to receive the light irradiated from the second light emitting portion and reflected by the uppermost sheet, disposed at a position different from that of the first detecting portion in a width direction orthogonal to the sheet feeding direction and so as to overlap with the stacking surface in a view of the height direction, and configured to detect a height position of the uppermost sheet at a position different from a detecting position of the first detecting portion in the width direction based on a time from when the second light emitting portion irradiates the light and until when the light irradiated from the second light emitting portion is received by the second photo-sensing portion; and 
 a control portion configured to start feeding the sheet stacked on the stacking surface by the feed portion and to stop feeding the sheet by the feed portion, 
 wherein the control portion is configured to stop feeding the sheet based on at least one of a height position detected by the first detecting portion and a height position detected by the second detecting portion in feeding the sheet. 
 
     
     
       20. An image forming apparatus, comprising:
 a sheet feeding apparatus comprising: 
 a stacking surface on which a sheet is stacked; 
 a feed portion configured to feed the sheet stacked on the stacking surface in a sheet feeding direction; 
 first and second detecting portions disposed at positions different from each other in a width direction orthogonal to the sheet feeding direction and so as to overlap with the stacking surface in a view from a height direction orthogonal to the stacking surface, the first and second detecting portions being configured to detect height positions which are positions in the height direction of an uppermost sheet stacked on the stacking surface at the respective positions in the width direction; and 
 a control portion configured to start feeding the sheet stacked on the stacking surface by the feed portion and to stop feeding the sheet by the feed portion, the control portion being configured to stop feeding the sheet based on at least one of a height position detected by the first detecting portion and a height position detected by the second detecting portion in feeding the sheet; 
 an image reading portion configured to read an image of the sheet fed by the sheet feeding apparatus; and 
 an image forming unit configured to form the image based on information of the image read by the image reading portion. 
 
     
     
       21. An image forming apparatus, comprising:
 a sheet feeding apparatus comprising: 
 a stacking surface on which a sheet is stacked; 
 a feed portion configured to feed the sheet stacked on the stacking surface in a sheet feeding direction; 
 a first detecting portion comprising a first light emitting portion configured to irradiate an uppermost sheet stacked on the stacking surface with light and a first photo-sensing portion configured to receive the light irradiated from the first light emitting portion and reflected by the uppermost sheet, disposed so as to overlap with the stacking surface in a view of a height direction orthogonal to the stacking surface, and configured to detect a height position which is a position of the uppermost sheet in the height direction based on a time from when the first light emitting portion irradiates the light and until when the light irradiated from the first light emitting portion is received by the first photo-sensing portion; 
 a second detecting portion comprising a second light emitting portion configured to irradiate the uppermost sheet stacked on the stacking surface with light and a second photo-sensing portion configured to receive the light irradiated from the second light emitting portion and reflected by the uppermost sheet, disposed at a position different from that of the first detecting portion in a width direction orthogonal to the sheet feeding direction and so as to overlap with the stacking surface in view of the height direction, and configured to detect a height position of the uppermost sheet at a position different from a detecting position of the first detecting portion in the width direction based on a time from when the second light emitting portion irradiates the light and until when the light irradiated from the second light emitting portion is received by the second photo-sensing portion; and 
 a control portion configured to start feeding the sheet stacked on the stacking surface by the feed portion and to stop feeding the sheet by the feed portion, the control portion being configured to stop feeding the sheet based on at least one of a height position detected by the first detecting portion and a height position detected by the second detecting portion in feeding the sheet; 
 an image reading portion configured to read an image of the sheet fed by the sheet feeding apparatus; and 
 an image forming unit configured to form the image based on information of the image read by the image reading portion. 
 
     
     
       22. A sheet feeding apparatus, comprising:
 a feeding tray comprising a stacking surface on which a sheet is stacked; 
 a feed roller configured to feed the sheet stacked on the stacking surface in a sheet feeding direction; 
 a first detecting sensor disposed so as to overlap with the stacking surface in a view of a height direction orthogonal to the stacking surface and being disposed at a first position in a width direction on a first side with respect to the feed roller, and comprising a first light emitting portion configured to irradiate a surface of the sheet on the stacking surface with light and a first light receiving portion configured to receive the light irradiated from the first light emitting portion and reflected by the surface of the sheet, the first detecting sensor being configured to detect a first height position which is a position of the sheet on the stacking surface in the height direction at the first position based on a quantity of light received by the first light receiving portion, the width direction being a direction which is orthogonal to the sheet feeding direction and the height direction; 
 a second detecting sensor disposed so as to overlap with the stacking surface in a view of the height direction and being disposed at a second position in the width direction on a second side with respect to the feed roller, and comprising a second light emitting portion configured to irradiate the surface of the sheet on the stacking surface with light and a second light receiving portion configured to receive the light irradiated from the second light emitting portion and reflected by the surface of the sheet, the second detecting sensor being configured to detect a second height position which is a position of the sheet on the stacking surface in the height direction at the second position based on a quantity of light received by the second light receiving portion; and 
 a controller configured to obtain the first height position detected by the first detecting sensor and the second height position detected by the second detecting sensor while the feed roller feeds the sheet, and configured to stop feeding the sheet based on the first and second height positions. 
 
     
     
       23. The sheet feeding apparatus according to  claim 22 , wherein the controller obtains a variation of the first height position before and in feeding the sheet by the feed roller and a variation of the second height position before and in feeding the sheet by the feed roller. 
     
     
       24. The sheet feeding apparatus according to  claim 23 , wherein the controller judges whether the sheet is a bound document based on the variation of the first height position before and in feeding the sheet by the feed roller and/or the variation of the second height position before and in feeding the sheet by the feed roller, and stops feeding the sheet by the feed roller if the controller judges the sheet is the bound document. 
     
     
       25. The sheet feeding apparatus according to  claim 24 , wherein the controller stops feeding the sheet by the feed roller in a case where the first height position detected by the first detecting sensor varies more than a predetermined value and/or where the second height position detected by the second detecting sensor varies more than a predetermined value. 
     
     
       26. The sheet feeding apparatus according to  claim 22 , wherein the controller stops feeding the sheet by the feed roller in a case where the first height position detected by the first detecting sensor exceeds a first threshold value and/or where the second height position detected by the second detecting sensor exceeds a second threshold value. 
     
     
       27. The sheet feeding apparatus according to  claim 26 , wherein the controller sets the first and second threshold values before feeding the sheet by the feed roller. 
     
     
       28. The sheet feeding apparatus according to  claim 22 , further comprising a separating portion configured to separate the sheet fed by the feed roller from another sheet at a separation nip. 
     
     
       29. The sheet feeding apparatus according to  claim 22 , wherein the first and second detecting sensors are disposed more upstream than the feed roller in the sheet feeding direction. 
     
     
       30. The sheet feeding apparatus according to  claim 22 , wherein the sheet feeding apparatus is an auto document feeder which feeds the sheet to an image reading unit configured to read an image on the sheet.